Age and growth studies provide critical data for clam fishery management. Three aging techniques, thin sections and acetate peel replicas – which involve shell sectioning – and surface growth rings were used to estimate the age and growth of Chamelea gallina populations in the mid-western Adriatic Sea. Their results were compared to identify the most reliable and least time-consuming approach. There were no significant differences between the two shell sectioning techniques (χ2 = 4.66, df = 3, p = 0.198), which were described by the same von Bertalanffy (VBF) growth curve parameters (L8 = 43.9, k = 0.26, t0 = −0.84), whereas significantly different L8 and k values were found between the two shell sectioning techniques and surface growth rings (L8: χ2 = 13.62, df = 1, p < 0.001; k: χ2 = 9.18, df = 1, p < 0.002; these statistics refer to the comparison between acetate peels and surface growth rings). The latter approach proved unreliable and error-prone, as it underestimated age and overestimated the growth rate (L8 = 26.4, k = 1.91, t0 = −0.11). Although the thin sections and acetate peel techniques both provide reliable age and growth estimates, the former approach was less time-consuming. Our analyses demonstrated that shell growth is slower in the cold season and in older specimens and that it has slowed down over the past few decades.

Age and Growth of Striped Venus Clam Chamelea gallina (Linnaeus, 1758) in the Mid-Western Adriatic Sea: A Comparison of Three Laboratory Techniques

Bargione G.
Primo
;
Petetta A.
Penultimo
;
2020

Abstract

Age and growth studies provide critical data for clam fishery management. Three aging techniques, thin sections and acetate peel replicas – which involve shell sectioning – and surface growth rings were used to estimate the age and growth of Chamelea gallina populations in the mid-western Adriatic Sea. Their results were compared to identify the most reliable and least time-consuming approach. There were no significant differences between the two shell sectioning techniques (χ2 = 4.66, df = 3, p = 0.198), which were described by the same von Bertalanffy (VBF) growth curve parameters (L8 = 43.9, k = 0.26, t0 = −0.84), whereas significantly different L8 and k values were found between the two shell sectioning techniques and surface growth rings (L8: χ2 = 13.62, df = 1, p < 0.001; k: χ2 = 9.18, df = 1, p < 0.002; these statistics refer to the comparison between acetate peels and surface growth rings). The latter approach proved unreliable and error-prone, as it underestimated age and overestimated the growth rate (L8 = 26.4, k = 1.91, t0 = −0.11). Although the thin sections and acetate peel techniques both provide reliable age and growth estimates, the former approach was less time-consuming. Our analyses demonstrated that shell growth is slower in the cold season and in older specimens and that it has slowed down over the past few decades.
Bargione G.; Vasapollo C.; Donato F.; Virgili M.; Petetta A.; Lucchetti A.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11585/796726
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